Another new feature appearing in Lion's Finder window Side Bar is AirDrop, a handy but limited means of sharing files between Wi-Fi-enabled Macs. Click on AirDrop and your Finder window turns into a radar-like image, with your own Mac at the foot of the window.

Any Macs within a ten-metre range that also have an AirDrop window open are also shown. To transfer a file to another Mac, you just drag and drop it onto its image in your AirDrop window. There's no setting up or configuring to be done, and as transfer is peer-to-peer, you don't even need to be on the same Wi-Fi network. It really is that simple.

Sharing with AirDrop is secure. After dragging a file onto another Mac's icon, you're asked to confirm you want to send it. The receiver can accept or decline – you can't drop files onto another person's Mac without permission. Transfer is encrypted, and neither party ever sees the files on the other's hard drive.

But although secure and convenient, AirDrop is also very limited. It can only transfer files between Macs running Lion; it's not available for earlier versions of Mac OS, and there's no Windows or Linux version for PCs. It's a useful feature if you regularly transfer small files between up-to-date Macs, but if you're in a mixed Mac and PC environment, or not every nearby Mac has been upgraded to Lion, you'd better not throw away that USB stick just yet.

TRANSFERS: AirDrop is a secure and convenient means of transferring files between Macs, but only if they're both running Lion

OS X's bundled email client has undergone some radical changes. A new widescreen view gives you a full-height window to view your mail, with received messages listed and previewed in a column on the left. Mailboxes and other folders aren't shown by default, but can be opened in another column at the push of a button. A favourites bar gives access to commonly-used folders, and you can customise it by adding new ones.

Messages can be flagged in seven different colours now, not just red, and the new Conversation feature threads on-going exchanges in chronological order, making them easier to follow. The search engine has had a radical rebuild, making it much easier to find what you're looking for. Mail is now compatible with Microsoft Exchange 2010 too.

Like Finder and iTunes, the button icons in Mail have gone stylishly monochrome, sometimes to the detriment of clarity. How, for example, are you supposed to know that a thumbs-down image means junk mail, or a square icon that looks like a washboard gives you a new note? When you first start using the revamped app, you might have to hover your mouse pointer over the buttons just to see what they do.

Perhaps it's strange that as the rest of Mac OS X becomes more tailored to the novice user, Mail gets more complicated and less instinctive. But Lion's email client is undoubtedly more capable than its predecessor, even if it isn't always as intuitive.

NEW MAIL:The new release of Apple Mail is more powerful, but less intuitive